An unarmed 18-year-old Missouri man who was shot multiple times by by a cop on Saturday was involved in an altercation with the officer before being killed, police said at a news conference on Sunday.

St. Louis County Police Chief Jon Belmar said Michael Brown, of Ferguson, Missouri, was struck "more than just a couple" times by gunshots fired by a Ferguson Police Department officer after a "physical confrontation" that began in a police vehicle and then spilled on to the street. The officer is now on paid administrative leave, Belmar said. The Ferguson Police Department reached out to Belmar immediately following the incident requesting that the St. Louis County Police Department launch an independent investigation, he said.

The shooting has sparked an outcry in the predominantly-black town of about 21,000 — a suburb of the city of St. Louis — and the local chapter of the NAACP has launched their own investigation into the case, appealing to the FBI for help. "We are hurt to hear that yet another teenaged boy has been slaughtered by law enforcement," St. Louis County NAACP President Esther Haywood said in a statement.

Hundreds of Brown's supporters swarmed the Ferguson Police Department for a second day on Sunday, expressing their disgust over the incident — which on Saturday included calls to "kill the police."